Fig. REF  shows the climatological annual cycles of \(\) , \(\)  in both hemispheres, and the meridional overturning streamfunction at 500 hPa, as well as theoretical estimates described below for each cell edge. The simulated cells are reasonably Earth-like in their meridional extent, overturning strength, and annual cycle phasing. In particular, \(\)  (solid red curve) migrates into either summer hemisphere but with a roughly 1-month lag behind the insolation, and its seasonal migrations (25.7S-23.2N) are several times larger than those of \(\) , (solid blue curves; 21.3-30.0N and 21.7-26.5S). Because the summer-hemisphere cell is so weak, \(\)  is only well defined in the winter half-month for either hemisphere (December through May for the northern hemisphere, June through November for the southern hemisphere). Compared to Earth, the \(\)  excursions into the summer hemisphere and cross-equatorial Hadley cell overturning strength are moderately excessive, while the simulated summer cell is too weak over most of the annual cycle. Finally, the transition from equinoctial to solsticial regimes is excessively rapid, approaching closer to the square-wave prediction of [1]} for axisymmetric atmospheres than Earth's more sinusoidal variations [2]}; in fact the annual-mean (not shown) rainfall and Hadley cells both show a double ITCZ resulting from this rapid jumping of the ascent rather deep into either summer hemisphere. These discrepancies are likely due to the rather shallow 10-m mixed layer, leading to excessively rapid seasonal transitions [3]}, [4]}.
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